Pressure liquid dispenser

ABSTRACT

A pressurised liquid dispenser, primarily for dispensing beer, in use, comprises an inner chamber ( 22 ) for said liquid, an outer chamber ( 15 ) for pressurised gas, the outer chamber surrounding the inner chamber, a casing ( 13:13   a ) of the inner chamber being of plastics material and connected to a casing ( 10:10   a ) of the outer chamber by ribs/webs ( 25:25   a ). A gas pressure regulator ( 24 ) is housed within the dispenser to reduce the pressure of the gas from the outer chamber to the inner chamber, and maintain the lower pressure in the inner chamber as liquid is dispensed therefrom.

This invention relates to a dispenser which is pressurised to dispense liquid, particularly, but not exclusively, beer.

With beer kegs, which are fed with pressurised gas to dispense the beer under pressure from the keg, it is important that a constant pressure is maintained on the beer, since if the pressure falls below an acceptable limit, the flavour of the beer suffers, i.e. it goes ‘flat’.

It is known in installations in public houses for the cylinder providing the pressurised gas to have a gas pressure regulator attached thereto so that the dispense pressure is set at the output of the regulator attached to the bulk gas cylinder kept in the public house. This pressure is then fed by a separate pressure line to a coupler which connects to a valve on the top of the keg.

In U.S. Pat. No. 3,561,649 there is described a container for storing and dispensing a liquid under pressure comprising a liquid chamber and a separate chamber for a pressurising fluid, with a pressure regulator for allowing the pressurising fluid to be introduced into the liquid chamber when the pressure therein is below a predetermined level. The container is made up of a generally cylindrical rear section to which a generally cylindrical front section is secured by a continuous internal weld, and a tapered section which is welded at its larger end to the front section. The liquid chamber is defined within the rear and tapered sections, whilst the pressurising fluid chamber is defined between the front section and the tapered section, with the pressure regulator in a wall of the tapered section.

It is an object of the invention to provide a dispenser in an improved form which is both effective and convenient.

According to the invention a dispenser comprises an outer chamber, which is intended to contain gas at a first pressure, in use, an inner chamber, which is intended to contain liquid to be dispensed therefrom, the outer chamber at least partly surrounding the inner chamber, and control means reducing the pressure of said gas, in use, from said first pressure in said outer chamber to a lower second pressure in said inner chamber, and maintaining said second pressure in said inner chamber as liquid is dispensed therefrom, in use, a plastics material casing of the inner chamber being connected to a casing of the outer chamber by a plurality of ribs/webs.

Preferably said outer chamber acts, in use, as an insulation layer to maintain chilled the liquid in said inner chamber. Desirably the outer chamber has a non-return valve for charging it with gas in an appropriate quantity and at an appropriate pressure. Conveniently liquid is dispensed, in use, from the inner chamber through a valve in an opening thereof. Advantageously the outer and inner chambers are each of U-shape in longitudinal cross-section, and of annular and circular shape respectively in lateral cross-section, and each rib/web in the outer chamber is of U-shape, with its respective free ends terminating short of an upper end of the outer chamber.

The invention also relates to such a dispenser which has been charged with said gas in its outer chamber and said liquid in its inner chamber.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic internal section of a dispenser of the invention,

FIG. 2 is an interior, part-sectional plan view of part of the interior of another embodiment of a dispenser of the invention, and

FIG. 3 is a section on line 3-3 of FIG. 2.

Illustrated in FIG. 1 is one embodiment of a dispenser according to the present invention. Although the dispenser is primarily intended for the dispensing of beer, and will be described in relation thereto hereinafter, it will be understood that it can be utilised for dispensing liquids other than beer. In its preferred embodiment the invention relates to a small keg for dispensing beer in restaurants or homes. By maintaining a constant pressure on the beer it is ensured that the taste, flavour and presentation of beer dispensed from the keg is optimised.

The dispenser comprises an outer casing 10 which is of generally cylindrical form having its top end open and its lower end formed with an inner convex domed portion 11 around the outside of which is formed an outer annular support portion 12 which, in use, rests on the surface, with the portion 11 disposed above said surface and the dispenser in an upright state. Within the outer casing 10 is an inner casing 13 which, like the outer casing 10, is generally cylindrical with its upper end open and at approximately the same level as the open end of the outer casing. The lowermost part of the inner casing is wholly domed, as at 14, the curvature of the part 14 matching the curvature of the portion 11. However the inner casing is spaced around both its cylindrical part and also its domed part from the outer casing so as to define by way of said spacing an outer, high pressure gas chamber denoted at 15. The inner casing is of plastics material, and whilst the outer casing is preferably also formed of plastics material, it could be of metal, for example aluminium.

The respective open upper ends of the casings 10 and 13 are together closed by a top closure portion 16 which is of generally domed form. However at its centre this portion 16 is provided with an upwardly extending, externally threaded boss 17 with a circular opening therethrough. Fitted at said boss is a valve denoted generally by the numeral 18. Extending from the valve 18 to a position close to the bottom inner surface of the inner casing 13 is an outlet pipe 19 for the discharge of liquid from the inner casing 13 through the valve 18. The valve 18 can be of known type of any suitable form, it merely being necessary that the outlet from the valve is sealed, for example by spring loading, in the normal state of the dispenser, depression of a sealing member against said spring loading, when liquid is to be dispensed, resulting in liquid from the interior of the casing 13 flowing upwardly through the outlet pipe 19 and then through the valve 18 and out of the dispenser.

At its outer periphery, the top closure portion 16 is formed with a downwardly depending annular flange 20 which seals with the upper open end of the outer casing 10 in any convenient manner. As shown in the drawing, the upper annular edge of the outer casing is received in a groove in the lower annular surface of the flange 20. Spaced inwardly of the annular flange 20 is a further downwardly depending annular flange 21, which is thus substantially parallel to the flange 20, this flange 21 having its inner surface sealing against the outer annular surface at the upper open end of the inner casing 13. Again, however, this sealing can be effected in any other suitable manner. In this way, the dispenser is in the form of a closed container comprising the outer high pressure gas chamber 15 between the inner and outer casings and, as will be described, an inner, lower pressure liquid chamber 22 in the space bounded by the top closure portion 16 and the inner casing 13 to which it is sealed by said flange 21.

At a position around the domed top closure portion 16, disposed immediately above the depending flanges 20 and 21, is formed an integral housing part 23 which contains control means in the form of a regulator 24. An inlet is provided into said regulator from said gas chamber 15, whilst an outlet is provided therefrom to the liquid chamber defined by the inner casing 13 and top closure portion 16. If required a vent hole to atmosphere can be provided at said housing part. Finally in the portion 11 there is provided centrally a non-return valve by means of which the gas chamber 15 can be charged with gas in the appropriate quantity and pressure, as will be described, to facilitate the dispense of liquid from the liquid chamber. However the means for charging the gas chamber 15 could be of any suitable form and at any other suitable position.

The inner casing 13 of the liquid chamber 22 is attached to the outer casing 10 of the gas chamber 15 by a number of equi-angularly spaced ribs or webs 25 which extend across the gas chamber 15 from the outer cylindrical surface of the casing 13 to the inner cylindrical surface of the casing 10. Preferably the ribs are of plastics material, but they could be metallic. They could be integral with one or both of the outer and inner casings, depending on the materials used therefor.

Additionally each rib or web 25 can also extend between the domed portion 14 and the domed portion 11, and also possibly between the domed portion 11 and support portion 12. As shown in FIG. 1, each rib or web terminates below the top of the gas chamber to allow the gas to flow around the whole chamber 15 despite the presence of the ribs or webs 25. Apertures could be provided in the ribs or webs to permit gas flow, and would be provided if each rib extended up to the top of the gas chamber, i.e. filled the chamber as a planar structure.

The use of the ribs or webs connecting the inner casing to the outer casing enables a strength and stiffness to be imparted to the fabric of the inner casing which would not otherwise be present. This strength is due to the casings being connected by a rigid rib or web. This strength is beneficial in that it allows the use of a suitable plastics material for the inner casing which is primarily suitable for contact with ‘food’ products, such as beer, but does not have the strength to withstand the total pressure. Structural strength is imparted to the inner casing by means of the ribs/webs, and the outer casing can be made of a much more structurally appropriate material, as it is not in contact with the beverage and thus does not have to meet food contact regulations. The pressure of the stored gas can thus be increased, providing an extension in the operating range of the dispenser whilst using a plastics material inner casing.

Compared to the US prior art container referred to in the introduction, the dispenser of the invention shown in FIG. 1 differs patentably in having at least its inner casing made of plastics, with the rigid support between the inner and outer casings allowing for a much stronger construction than with the unsupported equivalent prior art casings. Thus different materials can be used for the two casings, so as to obtain both the mechanical strength and also to meet the requirements for food contact.

In use the liquid chamber will be filled, or at least partly filled, with liquid to be dispensed, such, as described, as beer. The gas chamber 15 is charged with a suitable gas at a pressure higher than the dispense pressure required for the beer contained in the liquid chamber. The regulator 23 controls the gas pressure in the liquid chamber, by reducing the gas at the higher pressure in the gas chamber to a level in the liquid chamber which is that required for the correct dispense of the beer. Typically there would be a gas pressure in the chamber 15 of between 1 and 7 bars (10⁵ Nm⁻²to 7×10⁵ Nm²), whilst typically a dispense pressure of the liquid is between 0.5 to 2.5 bar (0.5×10⁵ Nm⁻² to 2.5×10⁵ Nm⁻²).

Whilst it is envisaged that the regulator would normally be pre-set so that a user cannot interfere with the pressure settings for dispense, this is not essential and the regulator could be of a type which is adjustable by a user. The maintenance of a constant dispense pressure is very important when dealing with beer, and the ability to maintain the required constant pressure as determined by the regulator setting is an important feature of the invention. With a liquid chamber it is 95% full of liquid pressurised at, for example 2 bar, then as that liquid is dispensed the whole of the liquid chamber has to be filled with the gas at the 2 bar pressure to maintain constant dispense pressure on the fluid. With the arrangement of the invention, this requirement is effectively met with the dispenser being in a compact and efficient form.

Although the keg described and illustrated is formed ‘all-in-one’, i.e. it incorporates the gas regulator, it is nevertheless of compact construction by having the gas chamber around the liquid chamber and having the reduction of the gas from high pressure to lower pressure carried out within a convenient part of the keg. This makes the keg particularly suitable for home use. The gas chamber also acts as an insulation layer, so that once the beer has been cooled, then the gas chamber acts as an insulator to maintain the beer in the liquid chamber at a chilled temperature.

Historically the dispense head of a keg has had to handle both gas and beer, in that gas must flow into the container to enable the beer to be dispensed from a tap connected to the valve on the top of the keg. With the keg of the invention, only the beer or other liquid is handled through the dispense head because the gas compensation into the liquid chamber is carried out automatically within the confines of the keg. The reduced pressure gas is fed directly into the liquid chamber without firstly having to come out of the high pressure gas cylinder through an external regulator and then back into the liquid chamber.

FIGS. 2 and 3 show an alternative form of arrangement for the outer and inner casings 10 a and 13 a respectively, namely that they are each of true U-shape in longitudinal (vertical) cross-section, with their respective free ends terminating at the same level. As can be seen in FIG. 3, the four U-shaped ribs/webs 25 a fill the gas chamber up to a level a short way below the top thereof, and provide the eight equi-angularly spaced ribs or webs shown in FIG. 2. The ribs/webs can be varied in number, need not be equi-angularly spaced, could extend to different heights in the U-shaped chamber and could be perforated. The ribs/webs interconnect the casings 10 a and 13 a and, as with the first embodiment, could be integral with one or both of the casings.

Suitable plastics materials for the inner casing include acetyl, polyamide, polyethylene terethalate, polyethylene and polypropylene. Such materials could also be used for the outer casing and/or the ribs/webs if these are of plastics material. 

1. A dispenser comprising an outer chamber, which is intended to contain a gas at a first pressure, in use, an inner chamber, which is intended to contain liquid to be dispensed therefrom, the outer chamber at least partly surrounding the inner chamber, and control means reducing the pressure of said gas, in use, from said first pressure in said outer chamber to a lower second pressure in said inner chamber, and maintaining said second pressure in said inner chamber as liquid is dispensed therefrom, in use, a plastics material casing of the inner chamber being connected to a casing of the outer chamber by a plurality of ribs/webs.
 2. A dispenser as claimed in claim 1, wherein the outer chamber acts, in use, as an insulation layer to maintain chilled the liquid in said inner chamber.
 3. A dispenser as claimed in claim 1, wherein the outer chamber has a non-return valve for charging it with gas in an appropriate quantity and at an appropriate pressure.
 4. A dispenser as claimed in claim 1, wherein liquid is dispensed, in use, from the inner chamber through a valve in an opening thereof.
 5. A dispenser as claimed in claim 1, wherein the outer chamber is of U-shape in longitudinal cross-section.
 6. A dispenser as claimed in claim 1, wherein the outer and inner chambers are of annular and circular shape respectively in lateral cross-section.
 7. A dispenser as claimed in claim 5, wherein each rib/web in the outer chamber is of U-shape.
 8. A dispenser as claimed in claim 7, wherein each rib has its free ends terminating short of an upper end of the outer chamber.
 9. A dispenser as claimed in claim 1, wherein the ribs are equi-spaced apart within the outer chamber.
 10. A dispenser as claimed in claim 1, wherein each rib is made of plastics material
 11. A dispenser as claimed in claim 1, wherein the casing of the outer chamber is made of plastics material
 12. A dispenser as claimed in claim 1, when charged with said gas in its outer chamber and said liquid in its inner chamber. 